1. Field of the Invention
The present invention relates to Dynamic Capacitance Compensation (DCC) for a Liquid Crystal Display (LCD), and more particularly, to an apparatus and method for performing Dynamic Capacitance Compensation (DCC) of a Liquid Crystal Display (LCD), capable of minimizing a chip size and reducing picture-quality deterioration.
2. Description of the Related Art
A Liquid Crystal Display (LCD) displays characters or images using optical variations caused by injecting and arranging liquid crystals between two glass plates and then applying a voltage to change the arrangement of the liquid crystal particles. Since the LCD uses a low voltage of 1.5 through 2 V, it has been widely employed in clocks, calculators, notebook computers, etc.
However, in the LCD, a current image overlaps a previous image due to a slow response speed, which produces blurring. In general, one frame has a duration of about 16.7 ms. When a voltage is applied to both ends of a liquid crystal material, the liquid crystal material responds to the voltage after a predetermined time has elapsed. Accordingly, in order to obtain a desired pixel value, a time delay is needed and such a time delay causes blurring.
In order to improve a response speed of the LCD, Dynamic Capacitance Compensation (DCC) is used. According to the DCC, a difference between a pixel value of a previous frame for an arbitrary pixel and a pixel value of a current frame for the pixel is obtained, and a sum of a value proportional to the difference and the pixel value of the current frame is output. In order to perform the DCC, the pixel values of previous frames must be stored in advance in a memory.
However, to store the pixel values of the previous frames without compression and stably perform the DCC, a write memory for storing the previous pixel values and a read memory for reading the stored pixel values and comparing the stored pixel values with current pixel values are required.
In order to reduce memory loads, a technique of compressing image data can be considered. That is, by compressing pixel values of a previous frame to bit streams using an encoder, storing the compressed bit streams in a memory, decoding the bit streams using a decoder, and comparing the decoded bit streams with pixel values of a current frame, DCC can be performed. Conventionally, color sampling compression has been used to compress pixel values of a previous frame. In the color sampling compression, pixel values of a previous frame are compressed by YCbCr sampling and down-sampling. Here, Y represents Luminance and Cb and Cr represent Chrominance.
However, such color sampling compression causes color changes when data is compressed and has low compression efficiency.
For these reasons, conventionally, to perform DCC in an LCD, a method of storing pixel values of image data for a previous frame without compression or a method of compressing pixel values of image data by color sampling compression with picture-quality deterioration has been used.